Effect of pilates mat exercises and conventional exercise programmes on transversus abdominis and obliquus internus abdominis activity: pilot randomised trial

Pilates training is said to increase Transversus abdominis (TrA) and Obliquus internus (OI) activation during exercise and functional activities. 34 Pain-free health club members with no Pilates experience, mean (SD) age 30(7) years, were randomised to Pilates mat exercises or strength training. Participants exercised unsupervised twice-weekly for eight weeks. TrA and OI thickness (a proxy for muscle activity at the low-medium efforts of our exercises) were measured with ultrasound pre- and post-training during Pilates exercises 'Imprint' (an abdominal drawing-in manoeuvre) and 'Hundreds A' (lying supine, arms slightly raised, hips and knees flexed to 90°) and 'Hundreds B' (as A, with neck flexion) and functional postures sitting and standing. Pilates participants had increased TrA thickness in Hundreds A all values mean (SD) mm]: 3.7(1.3) pre-intervention, 4.7(1.1) post-intervention (P = 0.007); and decreased OI muscle thickness during Imprint: 11.7(2.8) pre-intervention, 10.8(3.5) post-intervention (P = 0.008). Strength training participants had greater OI thickness during Imprint (P = 0.014), Hundreds A (P = 0.018) and Hundreds B (P = 0.004) than Pilates participants post-intervention. There were no changes in muscle thickness at rest or during functional postures. Pilates training appears to increase TrA activity but only when performing Pilates exercises. Further research is required into Pilates in clinical populations and how to increase deep abdominal activation during functional activities.